Prostate cancer (CaP) is the most common malignancy in American men and second leading cause of cancer mortality (Landis et al. (1999) Cancer J. Clin., 49:8-31; Jemal et al. (2004) Cancer J Clin 54:8-29). The molecular determinants in the development and progression of this disease are poorly understood. In recent years, there have been intensive investigations of molecular genetics of the CaP. To date, however, oncogene, tumor suppressor gene, or other gene alterations common to most CaPs have not been found. Alterations of tumor suppressors such as p53, PTEN and p27, or oncogenes such as BCL2, HER2 and C-MYC associate with only small subsets of primary CaP, with more frequent association observed in advanced CaP.
Current clinical parameters, including serum Prostate Specific Antigen (PSA), tumor stage, and Gleason score are routinely used as risk factors at the time of diagnosis, but have limited application to identify patients at a greater risk for developing aggressive CaP. Approximately 30-40% of patients treated with radical prostatectomy for localized CaP have been found to have microscopic disease that is not organ-confined and a significant portion of these patients relapse. (Singh et al., Cancer Cell (2000) 1:203-209; Henshell et al., Can. Res. (2003) 63: 4196-4203). Therefore, discovery of novel biomarkers or gene expression patterns defining CaP onset and progression is crucial in predicting patients with greater risk to develop aggressive CaP.
CaP-specific genetic alterations have been the subject of intensive research by several investigations in the past five years (Srikatan et al., In Prostate Cancer, Diagnosis and Surgical Treatment (2002) Springer-Verlag, 25-40; Karan et al., Int. J. Can. (2003) 103:285-293; Augustus et al., In Molecular Pathology of Early Cancer (1999) IOS press: 321-340; Moul et al., Clin Prostate Cancer (2002) 1:42-50; Lalani et al., Cancer and Mets Rev (1997) 16: 29-66; Issacs et al., Epidemiol Rev (2001) 23:36-41; Ozen et al., Anticancer Res (2000) 20:1905-1912; Morton et al., J Natl Med Assoc (1998) 90:S728-731). Promising leads both in biology and translational research areas are beginning to emerge from recent genomics and proteomics technology, as well as traditional approaches. However, the inherent heterogeneity of CaP has hampered the molecular characterization of CaP.
One of the challenges in studying molecular alterations in human cancers, including prostate tumors, is to define the relative contributions of genetic alterations in epithelial and non-epithelial components of the target organ in the process of tumorigeneis. Despite advances in technology, changes in human CaP-specific epithelial and stromal cell-associated gene expression are still not well understood.
Despite recent advances in the identification of molecular alterations associated with certain prostate cancers, the heterogeneous nature of prostate tissue has hindered the identification of genetic targets common to all, or at least the vast majority of, prostate cancers. The complexity and heterogeneity of prostate cancer has also hindered the identification of targets that allow differentiation between clinically aggressive and non-aggressive cancers at the time of diagnosis. Therefore, there remains a need to identify molecular alterations specific for a pathologically defined cell population that can provide important clues for optimal diagnosis and prognosis, and help to establish individualized treatments tailored to the molecular profile of the tumor.
Citation of references herein shall not be construed as an admission that such references are prior art to the present invention.